Patent US3625920A successfully refreshed from Google Patents.
US3625920A
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US
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Process for the production of carbonic acid polyesters
Assignee: INST TWORZYW SZTUCZNYCH WARSZA
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Filing: 1968-05-03
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Granted: 1971-12-07
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Expires: 1988-05-03
Abstract
Abstract Process for producing polycarbonate by transesterification reaction between aromatic monohydroxycarbonic ester and dihydroxy diphenyl alkane or phenol adduct thereof in presence of alkali metal salt of fluoroboric acid and/or hydroxyfluoroboric acid as catalysts and stabilizers.
Inventors
- 👤 Jan Borkowski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:40
CPC Classifications
C; C08; C08G; C08G64/00; C08G64/20; C08G64/30; C08G64/307
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
54 words
A process for producing polycarbonate according to claim 1 wherein said catalyst and stabilizer is a fluoroboric acid salt of an alkali metal selected from the group consisting of lithium, sodiUm, potassium, and rubidium which is present in an amount of up to 1 percent by weight based upon the amount of said compound.
Claim 2
Dependent Claim
51 words
A process for producing polycarbonate according to claim 1 wherein said catalyst and stabilizer is an hydroxyfluoroboric acid salt of an alkali metal selected from the group consisting of lithium, sodium, potassium and rubidium which is present in an amount up to 1 percent based upon the amount of said compound.
Claim 3
Dependent Claim
56 words
A process for producing polycarbonate according to claim 1 wherein up to 1 percent by weight based upon the amount of said compound of a fluoride of an alkali metal selected from the group consisting of lithium, sodium, potassium and rubidium and boric acid is present, which produces said catalyst and stabilizer under the reaction conditions.
Claim 4
Dependent Claim
73 words
A process for producing polycarbonate according to claim 1 wherein the alkali metal of the salt of said catalyst and stabilizer is selected from the group consisting of lithium, sodium, potassium and rubidium and said catalyst and stabilizer is combined with an alkali metal chloride and the amount present of said catalyst and stabilizer and said alkali metal chloride is up to 1 percent by weight based upon the amount of said compound.
Claim 5
Dependent Claim
33 words
A process for producing polycarbonate according to claim 1 wherein said catalyst and stabilizer is a mixture of said alkali metal salt of fluoroboric acid and said alkali metal salt of hydroxyfluoroboric acid.
Claim 6
Dependent Claim
44 words
A process for producing polycarbonate according to claim 1 wherein said catalyst and stabilizer is combined with tetraphenylsilane and said catalyst and stabilizer and said tetraphenylsilane are present in an amount up to 1 percent by weight based upon the amount of said compound.
Claim 7
Dependent Claim
21 words
A process for producing polycarbonate according to claim 1 wherein said compound is a phenol adduct of a dihydroxy diphenyl alkane.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-06 | 1975-06-07 | 1975-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-06 | 1979-06-07 | 1979-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-06 | 1983-06-07 | 1983-12-07 | $7700.00 | Window Closed / Lapsed |